Adsorbent compositions

ABSTRACT

A water vapor adsorption and water retaining composition containing particulate calcium chloride and particulate vermiculite in a flexible container having a side of spun-bonded polyethylene heat sealed to a side of extrusion coated polyethylene on polyester. The foregoing composition can also contain clay.

CROSS-REFERENCE TO RELATED APPLICATIONS

Not Applicable

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable

BACKGROUND OF THE INVENTION

The present invention relates to improved water vapor adsorption andwater retaining compositions.

By way of background, there are situations wherein products must beprotected from moisture in environments wherein there are wide swings intemperature and relative humidity.

BRIEF SUMMARY OF THE INVENTION

It is one object of the present invention to provide improved watervapor adsorption and water retaining compositions which will operatewell under conditions of wide swings in temperature and relativehumidity.

Another object of the present invention is to provide improved watervapor adsorption and water retaining compositions which will adsorbwater vapor and will retain the adsorbed water without appreciablyincreasing the volume of the composition.

A further object of the present invention is to provide improved watervapor adsorption and water retaining compositions containing waterretaining material which will hold a high multiple of its weight ofwater.

Another object of the present invention is to provide an improvedcontainer for a water vapor adsorbing and water retaining composition.Other objects and attendant advantages of the present invention willreadily be perceived hereafter.

The present invention relates to a water vapor adsorption and waterretaining composition comprising particulate calcium chloride andparticulate vermiculite.

The present invention also relates to a water vapor adsorbing and waterretaining composition comprising calcium chloride, vermiculite and clay.

The present invention also relates to a flexible container comprising aside of spun-bonded polyethylene and a side of extrusion coatedpolyethylene on polyester.

The present invention also relates to a water vapor adsorption and waterretaining composition comprising particulate calcium chloride andparticulate vermiculite in a flexible container having a side ofspun-bonded polyethylene and a side of extrusion coated polyethylene onpolyester.

The present invention also relates to a water vapor absorbing and waterretaining composition comprising particulate calcium chloride,vermiculite and clay in a flexible container comprising a side ofspun-bonded polyethylene and a side of extrusion coated polyethylene onpolyester.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

FIG. 1 is a plan view of a container containing the improved water vaporadsorption and water retaining composition of calcium chloride andvermiculite of the present invention;

FIG. 2 is a cross sectional view taken substantially along line 2—2 ofFIG. 1;

FIG. 3 is a cross sectional view taken substantially along line 3—3 ofFIG. 1;

FIG. 4 is a fragmentary enlarged cross sectional view takensubstantially along line 3—3 of FIG. 2;

FIG. 5 is a view similar to FIG. 4 but showing the container of FIG. 1containing the composition of calcium chloride, vermiculite and clay ofthe present invention;

FIG. 6 is a graph of a composition of calcium chloride and vermiculitefunctioning under the conditions stated thereon; and

FIG. 7 is a graph of a composition of calcium chloride, vermiculite andclay functioning under the conditions stated thereon.

DETAILED DESCRIPTION OF THE INVENTION

One embodiment of the improved water vapor adsorption and waterretaining composition of the present invention comprises particulatecalcium chloride C and particulate vermiculite V. The calcium chlorideis a deliquescent which has a high affinity for water vapor andtherefore works well under conditions of wide swings in temperature andrelative humidity. The calcium chloride and particulate vermiculite havethe capacity of absorbing and retaining approximately two and one-halftimes its weight of water without expanding appreciably.

Another embodiment of the present invention (FIG. 5) comprises calciumchloride C, vermiculite V and clay CL. The combination of calciumchloride, vermiculite and clay has the capacity of absorbing andretaining approximately 1.8 times its weight of water.

In the calcium chloride and vermiculite composition, the calciumchloride may be present in an amount by weight of between about 5% and90% and more preferably between about 12% and 50% and most preferablybetween about 20% and 35%.

The particulate calcium chloride is preferably of a mix having particlesof between about 0.6 mm and 4.7 mm. However, the size is not criticalinasmuch as the calcium chloride deliquesces into a syrupy solution andtherefore any reasonable size is acceptable.

In the calcium chloride and vermiculite composition, the vermiculite maybe present in an amount by weight of between about 25% and 95% amd morepreferably between about 45% and 85% and most preferably between about55% and 75%.

The particulate vermiculite may be of a size of between about 0.05 mmand 5 mm and more preferably between about 0.15 mm and 3 mm and mostpreferably between about 0.3 mm and 2.8 mm.

The composition of calcium chloride and vermiculite is produced bymixing the foregoing components in the desired relatively sufficientproportions.

In the calcium chloride, vermiculite and clay composition, the calciumchloride may be present in an amount by weight of between about 10% and30% and more preferably between about 15% and 25% and most preferablybetween about 15% and 20%.

In the calcium chloride, vermiculite and clay composition, thevermiculite may be present in an amount by weight of between about 5%and 80% and more preferably between about 40% and 75% and mostpreferably between about 60% and 70%.

In the calcium chloride, vermiculite and clay composition, the clay maybe present in an amount by weight of between about 5% and 75% and morepreferably between about 10% and 50% and most preferably between about15% and 20%.

The preferred clay is a bentonite type of clay. However, any suitableclay including but not limited to attapulgite and montmorillonite claymay be used.

The clay may be of a particle size of between about 0.5 inch and 200mesh and more preferably between about 0.25 inch and 50 mesh and mostpreferably between about 4 mesh and 40 mesh.

In the calcium chloride, vermiculite and clay composition, thevermiculite and calcium chloride may be of the sizes discussed aboverelative to the calcium chloride and vermiculite composition.

The composition of calcium chloride, vermiculite and clay is produced bymixing the foregoing components in the desired relatively sufficientproportions.

As can be seen from a comparison of the amount of calcium chloride inthe calcium chloride and vermiculite composition with an amount of thecalcium chloride in the calcium chloride, vermiculite and claycomposition, the latter is a much smaller percentage of the total weightof the composition. This makes the latter more suitable for use inenvironments where the corrosive tendency of the calcium chloride shouldbe minimized. Yet, the smaller amount of calcium chloride still providesan excellent amount of water absorption.

The illustrated flexible container 10 is fabricated of two sides offlexible sheet material and is approximately 10 inches long, 7 incheswide and about 1 ½ inches thick at its midpoint when it is filled witheach of the above compositions. The dimensions include a ½ inchheat-sealed border on all four sides. The container has a side 11 ofspun-bonded polyethylene having a thickness of 6.5 mils known under theregistered trademark TYVEK which is a product of E. I. DuPont de Nemours& Co. and has a designation 1059B. The other side 12 is an extrusioncoated composite having an extrusion coating 14 of 0.0020 inches ofpolyethylene on a base 15 of 0.00048 inches of polyester. This is acommercially obtainable product from Rollprint Packaging Products, Inc.,and it has a designation of RP0025. The polyethylene 11 is sealed to thepolyethylene 14. The container 10 having an extrusion coated composite12 is advantageous over prior flexible containers having a side which isan adhesive-bonded laminate because the adhesive has been eliminated andtherefore need not be taken into consideration relative to thepossibility of melting which could lead to delamination or otherwisedegrading during a heat-sealing operation.

In a preferred embodiment of the calcium chloride and vermiculitecomposition, the container 10 of FIG. 1 contains 50 grams of calciumchloride and 120 grams of vermiculite. The volume of calcium chloride isapproximately 50.8 cc and the volume of the vermiculite is approximately900 cc. The 120 grams of vermiculite will absorb approximately 480 gramsof liquid water which it receives in the form of a calcium chloridesolution. In the preferred embodiment, the calcium chloride is presentby weight in an amount of 29.4% and the vermiculite is present by weightin an amount of 70.6%. The vermiculite is of a mix having a size rangeof between about 0.6 mm and 2.4 mm. The calcium chloride, as notedabove, is of a mix having a size range of between about 0.6 mm to 4.7mm.

In a preferred embodiment of the calcium chloride, vermiculite and claycomposition, the container 10 of FIG. 1 contains 35 grams of calciumchloride and 115 grams of vermiculite and 35 grams of bentonite typeclay. The volume of calcium chloride is approximately 40 cc and thevolume of the vermiculite is approximately 815 cc and the volume of theclay is approximately 40 cc. The 150 grams of vermiculite and clay willabsorb and retain approximately 276 grams of liquid water which itreceives in the form of a calcium chloride solution. In the preferredembodiment, the calcium chloride is present by weight in an amount of19% and the vermiculite is present by weight in an amount of 62% and theclay is present by weight in an amount of 19% . The vermiculite is of amix having a size range of between about 0.6 mm and 2.4 mm. The calciumchloride, as noted above, is of a mix having a size range of betweenabout 0.6 mm to 4.7 mm and the clay is a mix having a size range ofbetween about 4 mesh and 40 mesh.

The vermiculite is, as is well known, a combination of silicon dioxide,aluminum oxide, magnesium oxide, calcium oxide, potassium oxide, ironoxide, titanium oxide and water. It is an accordion-shaped granulehaving a bulk density of between 4 and 10 pounds per cubic foot and,insofar as pertinent here, has a water-holding capacity of 220%-325% byweight and 20%-50% by volume. It is also known as a hydrated laminarmagnesium-aluminum-iron silicate.

The characteristics of the above described composition having 50 gramsof calcium chloride and 120 grams of vermiculite is shown in the graphof FIG. 6 which plots moisture adsorbed in grams against days at 85° F.and 90% relative humidity. It can be seen from the graph of FIG. 6 thatthe sample having a combined weight of 170 grams (50 grams of calciumchloride and 120 grams of vermiculite) will continuously adsorb andretain liquid water for over 70 days, and the amount at the end of about75 days is approximately 415 grams of water, and the curve is stillrising.

The characteristics of the above described composition having 35 gramsof calcium chloride, 115 grams of vermiculite and 35 grams of clay isshown in the graph of FIG. 7 which plots moisture adsorbed in gramsagainst days at 85° F. and 90% relative humidity. It can be seen fromthe graph of FIG. 7 that the sample having a combined weight of 185grams (35 grams of calcium chloride, 115 grams of vermiculite and 35grams of clay) will continuously adsorb and retain 276 grams of liquidwater over a 45-day period, and the amount at the end of 45 days isapproximately 276 grams of water, and the curve is still rising. Whilenot shown in the graph, at the end of 80 days, 333 grams of water wereabsorbed and retained.

While the above description has referred to a composition as consistingessentially of calcium chloride and vermiculite and another compositionconsisting essentially of calcium chloride, vermiculite and clay, itwill be appreciated that other minor components may be added forspecific purposes which do not appreciably alter the basic water-vaporadsorption and water retaining characteristics of the above-describedcompositions.

While preferred embodiments of the present invention have beendisclosed, it is to be understood that it is not limited thereto but maybe otherwise embodied within the scope of the following claims.

What is claimed is:
 1. A water vapor absorption and water retainingcomposition comprising particulate calcium chloride present by weight inan amount of between about 15% and 25%, particulate vermiculite presentby weight in an amount of between about 40% and 75% and clay present byweight in an amount of between about 10% and 50%.
 2. A composition asset forth in claim 1 wherein said calcium chloride is of a size ofbetween about 0.6 mm and 4.7 mm and wherein said vermiculite is of asize of between about 0.05 mm and 5 mm and wherein said clay is of asize of between about 0.5 inch and 200 mesh.
 3. A composition as setforth in claim 1 wherein said vermiculite is of a size of between about0.15 mm and 3 mm, and said clay is of a size of between about 0.25 inchand 40 mesh.
 4. A composition as set forth in claim 1 wherein saidcalcium chloride is present by weight in an amount of about 19%, andsaid vermiculite in an amount of about 62%, and said clay in an amountof about 19%.
 5. A composition as set forth in claim 1 wherein saidcalcium chloride is present by weight in an amount of between about 15%and 20%, and said vermiculite is present in an amount of between about60% and 70% and said clay is present in an amount of between about 15%and 20%.
 6. A composition as set forth in claim 5 wherein said calciumchloride is of a size of between about 0.6 mm and 4.7 mm and whereinsaid vermiculite is of a size of between about 0.3 mm and 2.8 mm andwherein said clay is of a size of between about 4 mesh and 20 mesh.
 7. Awater vapor absorption and water retaining composition consistingessentially of particulate calcium chloride present by weight in anamount of between about 15% and 25%, particulate vermiculite present byweight in an amount of between about 40% and 75% and clay present byweight in an amount of between about 10% and 50%.
 8. A composition asset forth in claim 7 wherein said calcium chloride is of a size ofbetween about 0.6 mm and 4.7 mm and wherein said vermiculite is of asize of between about 0.05 mm and 5 mm and wherein said clay is of asize of between about 0.5 inch and 200 mesh.
 9. A composition as setforth in claim 7 wherein said vermiculite is of a size of between about0.15 mm and 3 mm, and said clay is of a size of between about 0.25 inchand 40 mesh.
 10. A composition as set forth in claim 7 wherein saidcalcium chloride is present by weight in an amount of about 19%, andsaid vermiculite in an amount of about 62%, and said clay in an amountof about 19%.
 11. A composition as set forth in claim 7 wherein saidcalcium chloride is present by weight in an amount of between about 15%and 20%, and said vermiculite is present in an amount of between about60% and 70% and said clay is present in an amount of between about 15%and 20%.
 12. A composition as set forth in claim 11 wherein said calciumchloride is of a size of between about 0.6 mm and 4.7 mm and whereinsaid vermiculite is of a size of between about 0.3 mm and 2.8 mm andwherein said clay is of a size of between about 4 mesh and 20 mesh.